One embodiment of the invention relates to a centrifugal machine capable of managing the operation records of a rotor and, specifically, the invention relates to a centrifugal machine which can hold the operation record data of the rotor such as the number of rotations of the rotor and the total operation hours of the rotor.
A rotor (a rotating member), which is provided in a centrifugal machine for storing a specimen such as a cell and a gene, requires a high centrifugal acceleration and, therefore, it is necessary to rotate the rotor at a high speed, for example, at a speed of 100,000 min−1 (rpm). This increases a centrifugal stress which acts on the rotor and, therefore, when the rotor is used repeatedly, there is a fear that a fatigue failure can occur in a rotor material made of a titanium alloy, duralumin or the like. Thus, the rotor is treated as a part the life of which is limited and, specifically, the number of integrating operation rotations or integrating operation time of the rotor is regulated (for example, 5000 rotations or 10,000 hours). When the number of operation rotations or operation time of the rotor reaches a prescribed number, the rotor is considered to have reached its fatigue limit; and thus, at the then time, the use of the rotor is to be stopped, and the rotor is to be disposed. As described above, the rotor has a limited life and, in order to operate the rotor safely, it is necessary to manage the operation record of the rotor.
As a conventional method for managing the operation record of a rotor, as disclosed in the Japanese Patent Publication Hei-3-181347, there is proposed a method in which, in a rotor, there is provided a magnetic recording medium having a magnetic film, data are recorded and reproduced by a magnetic head, and the operation record management of the rotor is recorded in the rotor.
On the other hand, a specimen to be stored in the rotor of a centrifugal machine, in some cases, is required that it is held at a low temperature (for example, 4° C.) in order to keep it fresh. As an example of a method for controlling the temperature of a rotor, there is well known a method in which the temperature of a rotor is measured using a temperature sensor and a voltage to be applied to a Peltier element provided in a rotor chamber is controlled to thereby control the temperature of the specimen.
In the above-mentioned conventional centrifugal machine, a recording head is made to approach a rotor having a magnetic recording medium (a disk memory) for recording the operation record data of the rotor, whereby data on the rotor operation record are recorded into the magnetic recording medium, or the data are reproduced from the magnetic recording medium. Specifically, the present inventors have checked this conventional centrifugal machine for the mounting of the above-mentioned Peltier element for adjusting the temperature of the rotor chamber and have found the following problems.
That is, when, in the periphery of the rotor, the magnetic head and Peltier element are disposed adjacent to each other and a supply voltage for driving the Peltier element is controlled on/off, noise generated from the Peltier element is introduced into the input/output circuit of the magnetic head and, in reproducing the operation record data, a control device (a microcomputer) mistakes the thus introduced noise for the record data, resulting in the misreading of the data. Also, in recording the operation record data as well, the control device records the noise introduced to the magnetic head circuit by mistake.
To solve the above problems, there can be expected a method in which there is employed a shielding wire in order to prevent the noise from being introduced to the magnetic head circuit and a ferrite core is added to the magnetic head circuit to thereby absorb the noise. However, in this method, additional provision of electric parts increases the cost of the composing parts that are associated with the control device.